Manufacturing method for strained silicon wafer

A method for manufacturing a strained silicon wafer a threading dislocation density of 1×103 cm−2 or less, consisting essentially of:

• (a) preparing a single crystal silicon substrate;
• (b) forming a graded SiGe layer on the single crystal silicon substrate at a temperature ranging from 800° C. to 1100° C., the graded SiGe layer comprising a first Ge composition ratio progressively increased stepwisely from 5 to 60% atomic ratio;
• (c) forming a SiGe constant composition layer on the graded SiGe layer, the SiGe constant composition layer comprising a Ge composition ratio substantially equal to a Ge composition ratio at a surface of the graded SiGe layer which is adjacent to the SiGe constant composition layer;
• and
• (d) forming a strained Si layer comprising a thickness less than 15 nm on the SiGe constant composition layer,
• wherein (b) through (d) are performed at a temperature ranging from 800° C. to 1100° C. and under a reduced pressure atmosphere while the single crystal silicon substrate is rotated in a circumferential direction at a rate of 300 rpm to 1500 rpm.